Matching Analysis And Key Parameter Optimization Of A Traction Vehicle's Power Transmission System

With the improvement of the national living standard year by year,the national highway mileage increases year by year,the transportation industry will continue to develop,and the tractor as the representative of the short-and medium-distance freight transport,its status is still irreplaceable.At the same time,with the emission regulations becoming more and more stringent,in order to reduce transport costs,achieve high profits in the transport industry,improve the power performance of tractors and reduce fuel economy is the first problem to be solved by manufacturers.How to ensure the reasonable matching of power transmission system is very important to solve this problem.In this thesis,the traction vehicle of a cooperative manufacturer is taken as the research object.In order to improve the whole vehicle performance of the tractor,the matching optimization of the power transmission system of the tractor is carried out by using the method of simulation and calculation.Firstly,the comprehensive evaluation index of traction vehicle is established,then the whole vehicle model is established by CRUISE software for simulation calculation,and then the key parameters of power transmission system are optimized by the combined simulation of ISIGHT software and CRUISE.The following sketches have been completed:(1)This thesis summarizes the domestic and foreign development process and present situation,introduces the theory of dynamic matching and the basic theory of vehicle dynamics,and explains the new comprehensive evaluation system of power performance and fuel economy index.Then the power performance and fuel economy of the tractor are evaluated comprehensively.(2)Based on the existing tractor parameters,the whole vehicle model is established.The rationality of the whole vehicle model is analyzed based on the test results and the simulation calculation of the existing model.According to the requirements of dynamic and economic design indexes,the maximum speed,climbing slope,acceleration time of in situ start,acceleration time of overtaking and fuel consumption of 100 km at constant speed have been completed in the part of simulation.Simulation calculation of 100 km fuel consumption under cycle condition.According to the requirements of dynamic and economic design indexes,the maximum speed,climbing slope,acceleration time of in situ start,acceleration time of overtaking and fuel consumption of 100 km at constant speed have been completed in the part of simulation.Simulation calculation of 100 km fuel consumption under cycle condition.(3)The parameters of the power transmission system of the tractor are optimized by the joint simulation of ISIGHT software and CRUISE software.In the whole process,the speed ratio of the main reducer and the speed ratio of the transmission are selected as the design variables.At the same time,the acceleration time in situ is the dynamic objective function and the fuel consumption in multi-working conditions is the economic objective function,which is not only the double objective function,but also the NCGA genetic algorithm is used to model the optimization algorithm,and the optimal parameter value is obtained.(4)The optimal parameters are inputted into the whole vehicle model and the simulation results of dynamic performance and fuel economy after optimization are obtained.The rationality of the optimal parameters can be verified by comparing with the simulation results of the model before the optimization.